DMA reverts to PIO

Wed, 2007-07-11 08:30 by admin · Forum/category:

The stuttering DVD drive or the lame hard disk

Table of contents

for this article

Quick solution

This is the recommended solution. If you're not interested in the details, but just want to fix this problem as quickly as possible:

  1. Internet Explorer: click, Firefox and other browsers: right-click here.
  2. Internet Explorer: Despite any warnings click on the [Open] or [Execute] buttons as required to execute the file resetdma.vbs.

    Firefox and other browsers: Save the file resetdma.vbs to your hard disk. Double-click on the file in Windows Explorer and allow it to be executed.

    (If you fear that this web site could be malevolent, you could use the manual method instead, which is described below. You can also download, save, and inspect the program with an editor like the Windows Notepad. It is a script text file.)

  3. If the program found any ATA or SATA channel to reset, reboot your computer and test all drives.
  4. If the problem is still not solved, set the offending channel to PIO manually, reboot your computer, set the channel back to DMA, and reboot again.
  5. Please report your results here. Thanks!

Please note that this works only with the Windows drivers. If your device had its own manufacturer's drivers installed, this program cannot fix the problem and will not do anything to them. Instead it will report that no resettable DMA channels were found.

Note also that many CD and DVD drives only use UDMA-2, because their data rate is much lower than that of a hard disk. This is normal and no reason to worry.

If you are interested in the details, read on.

The program tries to reenable DMA in the registry exactly as described below, for all suitable (S)ATA channels. Windows then redetects the DMA status after the next reboot.

If you use the program again after a short while, it may again report that it has reset the channels. This is normal behavior and not a sign of any problem.

General description

This article also applies to Windows 2000. (Peter Frank reported successful application on Windows 2000 with Service Pack 4.)

DMA is an abbreviation for Direct Memory Access, an access method for external devices where the data transfer is not done by the central processor, but by a small special processor called DMA controller. It uses a procedure called cycle stealing, where the central processor memory access cycles are delayed for very short times to intersperse DMA controller memory access cycles. Some newer, faster DMA modes are called UDMA (Ultra DMA).

The alternative, slow and inefficient data transfer mode is called PIO, Programmed Input-Output, where the central processor transfers data byte for byte or word for word. This requires many processor commands for each data word and therefore causes a high and unwanted processor load.

A typical symptom of PIO mode is slow data transfer, accompanied by high processor load, leading, for example, to a choppy video display.

Possible causes for falling back to PIO mode

The most frequent use why a CD or DVD port falls back to PIO mode is a scratched or otherwise unreadable CD or DVD. For example, some newer DVDs, initially from Sony, carry a copy protection scheme that relies on defective sectors. If you try, without using special software, to copy such a DVD (which doesn't work), then this can already trigger the problem.

However, there are a few reasons why a computer may use PIO instead of DMA, particularly when it's the hard disk port that falls back, not a CD/DVD drive port. For example, David Duberman reported in 2005 that some Dell computers have DMA disabled in their BIOS by default for the second hard disk. So it is a good idea to check the BIOS settings first.

2007-05-13 – Jason Paquette confirmed that the BIOS setting in his Dell computer was wrong too and prevented DMA mode. Correcting the BIOS setting immediately enabled the DMA mode.

A not so rare hardware problem is a bad or too long IDE data cable. You need 80-way cables, not the older ones with only 40 wires. With poor cables the device may work, but Windows will probably step down to lower DMA speeds or even to PIO.

A further cause may be waking from standby mode, if one of the involved components does not perform this process correctly.

2007-02-20 – Stefan Welte wrote that on an Elitegroupsystems K7S5A computer all IDE hard disks ran in PIO mode, because automatic device recognition was disabled in the BIOS. (The computer booted from a SCSI disk.) Enabling device recognition solved the problem without any further measures.

2009-06-27 – markvm confirmed again that the BIOS in a Dell computer prevented DMA mode. Please see his comment below. In his case a hard disk was not recognized by the BIOS. After enabling and starting the automatic recognition, everything fell into place nicely, and DMA was automatically enabled by Windows.

2009-11-19 – flemur13013 mentioned again in this comment that setting the disk recognition to "Auto" in the BIOS settings solved his problem of a slow, CPU-gobbling secondary hard disk.

Occasionally a chip set or controller driver is buggy, so check with the manufacturer for updates.

2007-03-01 – Francois Eraud reports one such case in a Sony laptop, regarding an ALI M5229 chip set controller, solved with driver version 4.008.

2008-03-30 – Arran located the elusive drivers for this ALI M5229 controller chip. Please read his comment For those with the ALi M5229 IDE Controller in the comments on one of the next pages.

Other reasons can show up in the event log, so check this first and see if you can find repeated Atapi errors recorded. If so, you likely have a hardware defect. You can use the procedures described on this page, but your computer will probably fall back to PIO mode again and again, until you solve the underlying problem, which may be located inside the device, on the motherboard, or in the IDE data cable and its connectors.

A dramatic example was reported on 2006-12-29 by David Hähningen:

If you (half asleep in the dark and with considerable force) try to put the ATA plug on the hard disk the wrong way around, the gap called "KEYPIN" (pin 20 on the plug) pushes pin 21 of the hard disk socket and bends it aside. (This pin is responsible for DMA requests of the hard disk.)

As the disk can no longer reach the host with its requests, there is a communications problem, and Windows XP switches into PIO mode. A blessing in disguise: You can still save the data, though slower than usual. ;)

Few will succeed in repairing the disk. Just pulling the pin straight may not quite cut it, as the connection to the printed circuit board is probably broken.

2007-02-07 – Carl Kaufmann wrote that he looked for a solution for a computer with an Intel chip set and found the Intel(R) Application Accelerator. As instructed, he first installed the Intel Chip Set Installation Utility, which already solved the problem (as observed in Task Manager). He went on anyway to install the accelerator. After that there was no longer any DMA/PIO choice in the controller options, but everything now works right automatically.

2007-05-15 – John Schumacher confirms:

I thought I was having this problem, but that isn't the case. My BIOS listed Ultra DMA as being disabled on all my drives. I looked for the Advanced Settings tabs for the IDE channels in Device Manager, but the tabs were no longer there. I ran Nero InfoTool, which confusingly listed DMA on for primary and secondary masters, but off for primary and secondary slaves. After doing some more searching, I found out that the Intel Application Accelerator I recently installed is the culprit. Running Intel Application Accelerator confirmed that everything was OK.

The Intel Application Accelerator can also have a quite adverse effect when it is run on an unsuitable processor. If in doubt, uninstall it and retest. (See the comment, Intel Application Accelerator by dkneyle = Ausie Davo.)

The trap

Windows contains a trap in which quite a few computers seem to get caught sooner or later. The trap was described in a Web article whose link no longer works (and also in another one mentioned below):

The crucial paragraphs are:

PIO mode is enabled by default in the following situations:
For repeated DMA errors. Windows XP will turn off DMA mode for a device after encountering certain errors during data transfer operations. If more that six DMA transfer timeouts occur, Windows will turn off DMA and use only PIO mode on that device.

In this case, the user cannot turn on DMA for this device. The only option for the user who wants to enable DMA mode is to uninstall and reinstall the device.

Windows XP downgrades the Ultra DMA transfer mode after receiving more than six CRC errors. Whenever possible, the operating system will step down one UDMA mode at a time (from UDMA mode 4 to UDMA mode 3, and so on).

Of course, drive firmware being quite complex and certainly containing programming defects of its own, it is not all that difficult to produce such errors. In my case a scratched DVD and later also an unreadable (overburned) CD did the trick, got the drive to choke and Windows to disable DMA for good. Later my hard disk hiccupped just once and also went back to PIO for good.

I had been using my laptop for DVD viewing for years, until I inserted a borrowed and heavily scratched DVD. The player and apparently even the DVD drive choked on it, and when I finally got the DVD to play, I found that playing was jerky and processor load was 100%, roughly half of which was system overhead.

This indicated that the drive had reverted from the usual UDMA (Ultra Direct Memory Access) mode 2 to PIO (Programmed Input Output) mode. No amount of resetting or changing the relevant registry parameters from 1 (try DMA) to 2 (force DMA) helped. Stubbornly the drive kept using PIO mode, and Windows even changed these settings back to 0 (use PIO only).

The following text will refer to the secondary IDE port because that is more often affected, but essentially the same also holds for the primary IDE port, to which the main hard disk is connected in most computers.

Before you begin to work on the problem, log on as Administrator or as a user with administrator rights.

Check Your IDE Port Mode

First check what mode your secondary IDE port is currently working in. Go to Device Manager: right-click on My Computer, select Properties, click on the Hardware tag, click on the Device Manager button, click on the plus sign to the left of IDE ATA/ATAPI Controller, double-click on the secondary IDE channel, click on Extended Settings and check whether it is set to DMA when available. Directly underneath that setting is a grey field that shows the actual working mode of your IDE channel. You want the highest possible DMA or Ultra DMA mode there, and you definitely don't want PIO mode.

If the Extended Settings tab is not there, perhaps another driver is used, probably from the manufacturer of the IDE ATAPI controller. You can still perform a simple test. In the Task Manager activate the option View, Show kernel times. Then put a high load on the device, for example by copying a large file, and check whether the kernel times are minimal (red line). If you observe considerable kernel times, roughly around half of the total load, then the device is running in PIO mode, which is bad. The whole purpose of the DMA mode is to relieve the processor (in kernel mode) of this load.

Assuming the Microsoft IDE ATAPI driver, normally you don't have to use the registry editor, because the normal settings are also available through the properties dialog for the IDE port, but if you want to look at it anyway, the parameter for the secondary IDE port can be found through regedit.exe at


It is named Scsi only for historic reasons. Scsi Port 0 is the primary IDE port, to which presumably your hard disk is connected.

After trying various remedies—in vain—I found the abovementioned article and went to work again. I uninstalled the DVD drive in Device Manager and rebooted, but that did not help either.

So I searched for more and better information, then I went on and did the following.

Re-enable DMA using the Registry Editor

This chapter describes the manual way to do what the quick solution at the top of this page does automatically through a script program. If you're not interested in the details, you can back up to the chapter "Quick solution" above and run the script.

My thanks go to my fellow MVP Alexander Grigoriev who taught me this method.

Run REGEDIT. Go to the following key:


It has subkeys like 0000, 0001, 0002, etc. Normally 0001 is the primary IDE channel, 0002 the secondary, but other numbers can occur under certain circumstances. You have to go through these subkeys and check the DriverDesc value until you find the proper IDE channel.

Delete MasterIdDataChecksum or SlaveIdDataChecksum, depending on whether the device in question is attached as master or slave, but it can't actually hurt to delete both. Reboot. The drive DMA capabilities will be redetected.

Note that many CD and DVD drives only use UDMA-2, because their data rate is much lower than that of a hard disk. This is normal and no reason to worry.

2006-01-19 – Horst Schülke wrote that it is sufficient to empty the content of these values. But you can also delete the values entirely. Windows will automatically recreate them anyway, with new content.

Open Device Manager again and check whether the device is now actually using DMA mode. If so, congratulations, you've made it (at least until the next time Windows disables DMA). If not, you may have to change the IDE channel setting from PIO back to the highest available DMA mode and reboot again.

Many thanks to Tomáš Souček, Peter Götz, Alex Vaillant, and Cory Culbertson for piecing together the following information:

There are three keys that work together:


Each bit in these values means a transfer mode that the device may or may not be capable of. Somewhere at MS some of these bits can be looked up.


This is the actual mode the device is running at.


This entry may be the problem child. Peter wrote: "Normally not present in XP, it is created as a reaction to errors. This entry has absolute priority." However, there are doubts whether this is the absolute truth. It is still not entirely clear where this entry comes from. Erasing it or setting it to a DWORD value of 0xFFFFFFFF, rebooting, re-enabling DMA mode, and rebooting again seems to have solved the problem in some cases.


This entry contains the user's setting, manually entered in the advanced device properties. Has the same structure as MasterDeviceTimingMode. This entry appears when the user sets a limited mode manually, such as PIO only.

Another key that seems to create the problem is MasterIdDataChecksum.

All these parameters also exist for the slave drive as SlaveDeviceTimingMode, etc.

More information is needed. If you know anything, please click on Add new comment at the end of this article and write it down.

Alternative Method—Uninstalling the Port

1. Uninstall the secondary IDE port

Attention: Do this only if you use the Microsoft IDE driver that comes with Windows or if you have the driver on hand, because otherwise you may find yourself unable to reinstall the proper driver.

To uninstall the port along with its driver, open Device Manager as follows. Right-click on My Computer, select Properties, click on the Hardware tag, click on the Device Manager button, click on the plus sign to the left of IDE ATA/ATAPI Controller, right-click on Secondary IDE Channel, click on Uninstall. Deactivating is not enough.

Reboot to make the changes active and permanent.

After booting Windows will automatically reinstall the IDE channel and the DVD (or CD) drive. This Plug-n-Play process can take a little while, so give it a minute after the boot process finishes.

2. Check or reactivate DMA

But this may not always be not enough, because unfortunately Windows does not always automatically activate DMA on a DVD or CD drive. You have to check and, if necessary, tell Windows to try to use DMA first. It is possible that Windows XP with Service Pack 2 re-enables DMA automatically on reboot, but I have not tested this yet.

To re-enable DMA, go to Device Manager again. Right-click on My Computer, select Properties, click on the Hardware tag, click on the Device Manager button, click on the plus sign to the left of IDE ATA/ATAPI Controller, double-click on the secondary IDE channel, click on Extended Settings and change the relevant setting from PIO only to DMA when available.

On Windows NT and 2000 you now have to reboot a second time, but Windows XP applies the change instantly. Then you can go to the same place in Device Manager again and check whether the device is now actually using DMA mode. If so, all is well.

Note that many CD and DVD drives only use UDMA-2, because their data rate is much lower than that of a hard disk. This is normal and no reason to worry.

3. Driver is not intended for this platform

If you keep getting the following error message, please read on:

There is a problem installing this hardware.

IDE channel

An error occurred during the installation of the device. Driver is not intended for this platform.

2005-03-30 – Johannes B. wrote: The reason for this error is often that Daemon Tools or Alcohol 120% are installed. In this case the solution described below would not work. But when you uninstall these programs and then restart Windows, it will then install the device drivers without any further problems.

If these programs are not installed, then one possible way out is to rename C:\WINDOWS\system32\drivers\atapi.sys (or a similar path on your computer) to something like atapi.old.

If that's not possible, you can try it from the repair console (boot from the Windows install CD and select the repair console).

If Windows always automatically recreates atapi.sys, you can try renaming it in safe mode or from a command line window or you can try to rename or remove it in the driver cache as well.

Desensitize Your Computer's IDE or SATA Channels

There's a bit more to it. The following article offers a way to reduce the incidence of this problem, although it still doesn't solve it altogether.

IDE ATA and ATAPI Disks Use PIO Mode After Multiple Time-Out or CRC Errors Occur

Do read this article because it contains a useful long-term workaround. But you have to go through the procedure described here to re-enable DMA first.

Assuming you've done that, insert the ResetErrorCountersOnSuccess registry values mentioned in this article into both the primary and the secondary IDE port registry keys as described.

Unfortunately this is only a half solution, because when you enter an unreadable DVD, you will get 6 errors in a row, and the IDE channel will revert to PIO mode, but at least when you pull out the DVD in time and then insert a good one, the error counter will be reset and it will at least be a bit more difficult for Windows to hobble your IDE drive.

A little warning: One user reported that by mistakenly putting the value into the parent key, rather than into one of the 0000, 0001, 0002, etc., subkeys, he was accused by Microsoft's Genuine Advantage check of using a pirated copy of Windows and therefore denied online updates.


Useful info on re-enabling DMA. No more jerky video from primary slave! Thank you

Thank you for a very helpful article. After applying your fix I saw a 10x speed improvement!

Don't mention it!!! After months of trouble-free operation, DVD playback suddenly started to crap out on me, and your site was the only one I could find that remedied this problem. I had been trying to fix it for several weeks when I found it, and boy was I happy. I'm the one who needs to thank *you*!!! Thank you!!! :)

Thank you for the great page on DMA/PIO issues. I had a problem caused by Daemon tools that you covered on your page. Without your work I might never have solved this problem. I intend on donating again after my next paycheck.

You ROCK! Your write-up on Windows setting DMA back to PIO saved me. I was about to take a 12 gauge to my computer. My DVD player wouldn't work for SHIT (stuttering, dropping frames, etc.). I uninstalled my secondary IDE controller, re-booted, & problem solved. THANKS!

Your DMA reverts to PIO page relieved me from horrible sound stututustuttuttering. [...] Hard disk went from PIO mode back to Ultra DMA mode 5 when I uninstalled primary IDE channel in device manager and XP reinstalled it. Thanks.

I love you...
no i don't—but I'm really greatfull that you published this site [...] as I was quite desperate and 24 hours mentally down because my harddisk only managed 2,2 MB/sec (now, thanks to you: 66,2)
best wishes!

Wonderful Dude,
I just want you to know that your posts on how to fix choppy DVD players saved my butt tonight. I love the fact that I can go and search for an answer on the internet, and a good soul such as yourself will have taken the time to post such a clear and excellent series of solutions. [...]

I just wanted to thank you for the information [on this page]. After noticing that my laptop's CD/DVD drive started exhibiting the dreaded "choppy playback" from nowhere (probably caused by trying to read a poorly burned homework assignment handed out by one of my professors a dozen times) I found your advice after a quick search on how to correct the problem. After a few minutes of reading, using the provided script, and rebooting, my drive successfully reverted back to DMA mode from PIO.
Just wanted to give my thanks and have myself counted among the satisfied visitors who were able to fix the issue without any problems. I especially appreciated the down-to-earth explanations for and solution to the playback choppiness. CDs/DVDs play like a dream again, and that really makes my day.

I also wanted to thank you. I almost despaired. For no discernible reason all movies from my DVD drive became jerky. Cleaning the registry and scanning for viruses were also unsuccessful. I was already resigned to the thought of returning the laptop to the manufacturer, because I thought the drive was broken. Luckily there is the Internet and dedicated people like you, who help with good tips.
Many thanks for your work; the article is truly excellent. You're my savior, unthinkable now that I had almost reinstalled the computer.
I hope that many, who have the same problem, find your article.

Thank you very much for your online help to my DMA problem (DMA reverts to PIO). I had been banging my head against the wall for a few weeks before I found your site. The .vbs program worked perfectly to fix my infuriating iTunes & audio distortion problems. For this, I have donated $10 to your site.

Comments, discussion

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Typical symptom: PIO mode (see comment 761). JPG image30.33 KB

Secondary slave device 1 current transfer mode says Not Applicab

Fri, 2009-11-27 20:00 by anuli

With ur help I could reset dma in secondary device 0 to ultra mode 2. Slave IDDataCheckSum is missing in secondary registry as well as upper & lower filters.

Slow PIO mode 2nd IDE disk - sony Vaio BIOS fix

Thu, 2009-11-19 17:45 by flemur13013

Hi - thanks for the website and info.

Here's some info for others: I added a 2nd IDE disk to a previously working-fine sony RX850 dekstop, and it used 90%+ Interrupts CPU and was noticeably slow (using 'HDtach' for testing, and doing backups).

This didn't work:
- Uninstalling IDE drivers / rebooting
- the VBS script here / rebooting.

This worked:
- Getting into the BIOS and setting the detection of the 2nd disk to 'Auto' !!!


BIOS setting

Thu, 2009-11-19 19:15 by admin

Thanks for this info. This problem was mentioned some time ago already, so it may not be as rare as one might think. I'll mention it in the main article.

The Trap and The Cause-PIO mode triggered

Tue, 2009-11-03 04:38 by Greatful1

Let's say you like to copy DVD's. Many protected DVD's have built-in errors to prevent easy copies.
The "Attempt" to copy, not "play" the DVD will trigger this problem.
When you "play" the DVD, it skips around the built-in formatted errors.
I think the manufacturers should be shot, but that's a different discussion.
So...If you copy protected DVD's (or CD's I presume), keep the reset tool handy!
BTW: Worked great for me. Thanks for the time-effort.
Donation on the way....:-)

Oh, that's terrible!

Tue, 2009-11-03 09:01 by admin

First of all, thanks a lot for your donation! A little money to support this web site is always very welcome. As a tiny reward you now have your own, personal blog here.

I know the DVD copy protection schemes, but it never dawned on me that simply trying to copy such a DVD could easily trigger this DMA step-down towards PIO defect. Now that you've said it, it seems pretty obvious.

Thanks a lot, I'm now mentioning this in the first paragraph of the chapter linked here.

We should also mention that an attempt to copy one of these copy-protected DVDs will fail anyway, unless special software is used.

One of the more evil copy protection schemes, introduced by Sony, consists of liberally sprinkling defective sectors all over the DVD and design the IFO DVD structure definition files such that a DVD player will skip over them. Needless to say, only software that understands the DVD data structure is able to do that. Even some older DVD ripping software that relies on ignoring and skipping errors after they are detected may well trip our problem.

IDE-4008.exe driver

Wed, 2009-10-28 22:27 by jdoherty76

I tried everything in this thread to reset my drive from PMI but to no avail. Finally I noticed someone discuss the chipset ALI M5229 and driver IDE-4000. This is the same chipset I have on my Sony Vaio. I installed this and it appears to work a treat. Question when I look in device manager under IDE ATA/ATAPI controllers there is a subtab that is called ALI Ultra IDE controller properties and the general tab has the following:

No drivers are installed for this device.

If you are having problems with this device, click Troubleshoot to start the troubleshooter.

The driver tab looks okay...So I cannot confirm whether or not I am in DMA mode or not but my PC is certainly responding a lot faster than previously. Is this correct? should I see the advanced tab with the mode I am running? (similair to the way it was before I installed this driver)

One other question if I wanted to uninstall/rollback this driver how would I return to the previous driver I had as I did not take a note of it. Help and advice as always appreciated. Thanks JD

This was my fix - sony vaio laptop on xp sp2

Sat, 2009-12-05 23:25 by chilismaug

I tried the vbs and registry fixes to no avail. MS also has a kb #817472 hotfix for XP SP1, but I am on SP2 and that did not work. I think the SP2 had already made those registry key fixes.

I had upgraded to a larger hard drive - silly me. The Sony uses the ALi IDE driver and apparently the same problem bemoaned below by the HP user is at work. I found that 4800 driver installer and ran it. After several reboots, Windows gave its default startup sound without any fluttering, which is another symptom of the loss of DMA. I also noticed the login response was a little snappier.

As described by jdoherty76, my Device manager also no longer displays the IDE sub-entries for the primary/secondary channels but it works so no worries. Now I can actually play MP3s and run other programs at the same time. Hooray!

ALI driver

Wed, 2009-10-28 22:54 by admin

I don't know the ALI driver, so I cannot tell. It looks though as if it isn't installed perfectly. It may still work. You could measure the speed to find out, using a disk speed test.

There is a button to roll back a driver. Don't know where exactly it is in Vista, but it shouldn't be difficult to find. In XP it is on the driver tab and says "Installed driver".

update to ATI Driver thread

Thu, 2009-10-29 08:26 by jdoherty76

Actually upon re-reading my original post I don't think it was very clear. Since installing the new driver I don't have a prinary and secondary IDE channel properties box. Not sure if this is correct or not but laptop does appear to be performing a lot quicker than previously. thanks JD

Quick Solution doesn`t work

Mon, 2009-10-26 23:06 by Internetagentur...

Hi, the quick solution doesn`t work. Whats wrong? Did any one got another quick solution for me?

Please read before writing

Tue, 2009-10-27 10:11 by admin

The article explains in detail when and why the quick solution does and does not work.

Please Help 10 20 2009 Same DMA/PIO Problems

Wed, 2009-10-21 00:45 by tneve

Help needed, Please. DMA - PIO problems. Windows XP (build 2600: Service Pack 3), Computer 8 Intel CPU 1.601GHz, Chip Set Intel unknown(Dev=25c0). PCI Latency Timer 0. Hard Disk Performance for C-Drive (HDD Test) Results C-Drive Read 2357KB/S - Write 2051KB/S.

In my Device Manager under: + IDE ATA/ATAPI controllers, I have written down the current settings for you to please review. I am not sure what I need to do, or how to applie the Text from the link to your solution. Please if you could, advise me of any recommendations on how to proceed to correct the problem, or to speed up this C-Drive of a HD Video Eiting System. The C-Drive speeds are too slow to edit with. Please advise to email: Thank you . Please See Setting Below:

1st item listed is:

Intel 631xESB/6321ESB Ultra ATA storage Controller - 269E
PCI bus 0, device 3, function1
working properly.
Driver Version: - Date 11/5/2006 Microsoft Windows Hardware Compatibility
No conflicts listed

2nd item listed is : General Tab

Primary IDE Channel
Device type: IDE ATA/ATAPI controllers
Manufacture: (Standard IDE ATA?ARAPI controllers)
Location: Primary Channel
Status - Working Properly

Advance Tab Settings:

Device 0
Device Type: Auto Detection
Transfer Mode: DMA if available
Current Transfer Mode: PIO Mode

Device 1
Device Type: Auto Detection
Transfer Mode: DMA if available
Current Transfer Mode: Ultra DMA Mode 2

Driver Provider: Microsoft
Date: 7/1/2001
Version: 5.1.2600.2180

I Thank you in advance for your knowledge and your kindness to help. If you need additional information please let me know.


Quick solution

Wed, 2009-10-21 14:52 by admin

Just perform the quick solution. That will probably solve the problem.

kaz's picture

Quick solution link

Fri, 2009-10-23 18:10 by kaz

I think his problem and it was mine too was that clicking the quick solution link only opens a page of text and doesn't do anything after that. Is it supposed to run a program? I was able to solve my PIO problem with the help of this page and following the directions in this link though.

I installed the MS hotfix then edited my registry with the instructions provided and that did the trick.

Quick Solution Link

Tue, 2009-12-29 17:49 by lotsmorewine

I had the same problem with the link using Firefox, but it worked fine with Internet Explorer. I thought I'd trashed my laptop after running with a very intermittent, temporary power supply. Symptoms included very high CPU usage, slow loading, slow running and stuttering audio. I didn't understand what the underlying problem was, but the quick solution seems to have cured them all! Thank you very much.

Ah, Firefox does it differently!

Tue, 2009-12-29 20:58 by admin

Sorry, I had never tested the link in Firefox. Will add instructions to the main article.

Thanks a lot for drawing my attention to this problem.

Quick solution

Fri, 2009-10-23 22:09 by admin

Yes, the link you mention is already mentioned in the main article, in the chapter Desensitize Your Computer's IDE Channels.

The Quick solution link gives you a Visual Basic Script (vbs) program. Every normal, up-to-date Windows XP installion contains the Windows Script Host (wscript.exe and cscript.exe in the system32 folder) that is needed to run that program. If your Windows does not run it, then something is wrong. My first guess would be that automatic updates are switched off or failing and the current service pack is not installed either, which is a dangerous proposition.

On a normal Windows installation, if you click the Quick solution link, you get a first question asking whether you want to download the file, then a second one whether you want to run it, then a third announcement from the program itself that explains what the program is about to do and still gives you an opportunity to cancel. Answer all three questions in the affirmative, and the DMA-PIO problem is instantly solved.

Alternatively you can download the file, store it with the filename resetdma.vbs, then examine and run it.

kaz's picture

system32 folder seems like the problem

Sat, 2009-10-24 15:01 by kaz

I ran winver and it says i have Build 2600.xpsp_sp3 so that seems up to date. Then I ran msconfig and made sure The automatic updates service was enabled which it was. Then I checked the system32 folder in the i386 file and found only NTDLL.DLL and an SMSS application. No sign of the wscript.exe or cscript.exe. Is this a problem?

My PIO issues are fixed for now but will missing the Windows Script Host cause other issues?


No Windows Script Host

Sat, 2009-10-24 16:21 by admin

Please read this article.

Apart from our quick solution program you may not need WSH any time soon, so there may not be any urgency to install it.


Tue, 2009-10-20 01:45 by capsize

My friend, thank you thank you thank you!!!

This laptop was about 1 minute from being smashed until I found your post.

I used the procedure of identifying the port mode, which I found to be PIO. I deleted the 2 registry entries described above, rebooted and confirmed that the mode was now running in UltraDMA5, and was able to watch a streaming video without the stuttering and skipping Such an easy fix, but its been about 2 years of a search, and dealing with the frustration.

I, as everyone else had, figured it was some kind of malware or driver fault. Nope. it was PIO (Pain Inthe O-hole). :)

It also boots much faster now too.


Thanks . I am going to recomend this site to all I know!

Mon, 2009-08-31 13:33 by Surya

I have been having this problem of stuttering audio from CD and now because of this script its solved. This site means what it says. Great days are ahead of you people, keep it up. And thanks once again.


Mon, 2009-08-31 12:11 by defo (not verified)

Thank you for script. Problems in 3dmax and Photoshop is over!

The script is very helpful in

Tue, 2009-10-13 05:33 by careertargetph (not verified)

The script is very helpful in my part.

Audio and video skipping, stuttering, slow xp boot/ start up

Thu, 2009-08-27 08:28 by audioskipper

I've Exhausted almost all sources!!!!!!!!! but found A SOLUTION FINALLY..

I had this very same problem just recently, and I even reformatted twice and I tried everything in this site i have ran though all the comments, and a dozen more on other sites but none of it worked, but I kept on searchign online until I stumbled onto this site and VOILA!!!!!!! it was just one simple thing and wow i mean WOW i can finally watch and listen smoothly and start up well.

Here is the UNDENIABLY helpful site (at least it was for me). I hope it will help others who have had the same problem.

GabbyJim's picture

DVD / CD sound stutters - sounds like two apps out of sync

Wed, 2009-08-26 04:48 by GabbyJim

For no apparent reason my DVD/CD player began to play the sound as an overlapping echo

Thanks to SUPE for the fix - hopefully I'll not be back - he included a link to - "The stuttering DVD drive or the lame hard disk" - a simple registery edit solved the problem. Who knew a bad cd / dvd could cause DMA to revert to PIO? I simply went to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318} and deleted the sub-keys 0000, 0001, and 0002 (after backing up the registry, "just in case" )- then a reboot and all was well!

Too bad the thread was closed - I hope it stays available forever, as some of us old turkeys can not justify a new computer - may mine last until I croak!

Thread open

Wed, 2009-08-26 06:16 by admin

Thanks for reporting back. This thread here is certainly not closed (you can add comments and replies) and will probably remain open as long as the problem exists. I have moved your message over here.

Perhaps you saw that your new comment was unpublished. That is only an unfortunate consequence of the increasing number of spammers who try to post advertising here. Currently new comments stay unpublished until I check and publish them.

mish_moonlight's picture

Thanks very much!

Thu, 2009-08-06 13:35 by mish_moonlight

I have been searching for ways to fix the stuttering for months now. I was about to lose hope when finally I found this COOL site. This, by the way, is the only solution that worked. Thanks again and I hope everyone here get to finally watch movies stutter-free!


Tue, 2009-06-30 00:00 by jobykinobe

I can't thank you enough!!! the vbs worked a treat for a painfully slow startup on Win xp on my Asus A6 series laptop. Impossibly slow startup, processing and the stuttering sound is now fixed. You are my heroes :)

BIOS settings: DELL

Sat, 2009-06-27 20:56 by markvm

Thanks for all the help and explanation here.

The quick fix didn't solve the problem for me - a hard drive which was using PIO.

However, I followed the suggestion to look at the BIOS and discovered that it only knew about my primary HD and my DVD. My second HD was not there.

I changed the BIOS setting to auto-detect for the second slave device (where the new HD was) and, after a heart-stopping 30 seconds while the BIOS interrogated the IDE devices and I thought I had destroyed everything, the BIOS now knows about all my disks.

Didn't even have to re-run the fix - windows automatically upped the port to UDMA when I rebooted.

Haven't had time to see if the performance has improved, but as I had moved my swap file to the second drive I imagine it will be pretty clear!


BIOS preventing DMA

Sun, 2009-06-28 08:49 by admin

Thanks for reporting this. We have had some similar reports, but never quite the same case.

Your comment is now also cited and linked to in the main article at the top.

Thank you!

Thu, 2009-06-18 21:14 by daemon87

(Just wanted to add to the thanks list...)
Great job on saving our computers from frustration-related accidents :) I had the choppy-sound, sudden performance decrease symptoms.
After countless driver reinstalls and reboots and hours spent searching the internet, i came across you guys! the simple solutions really are the best! read the post->looked at my hardware settings: PIO! applied your script->rebooted-> presto! UDMA mode 6 :D
Once again, thank you!

I cannot understand the directions to solve my sound distortion

Mon, 2009-10-12 09:11 by dreamtoys


Due to English limitation, I could not understand all instructions and can someone hold my hand and give me exact step by step way of fixing my sound distortin problem. It showed PIO in my primary and ulter DMA in the secondary. Please send answer to too as I may missed your posting on this site. Tx


PIO to Ultra DMA Fix!

Sat, 2009-05-30 21:26 by joe pau

Thanks for the great work. I was given a slow, skipping, long loading o/s laptop. I ran the script and Viola! It worked. It's like the computer is brand new and operates perfectly. Thanks for the info. You folks Rock!

Step 1

Sat, 2009-05-30 20:54 by AntonShuma

I am pressing step 1 but nothing happens is there a way to activate that command.
I tried doing it manually but no luck so far. My DVD sound is horrendous.

Finally solved!

Thu, 2009-05-28 07:35 by zordon

Re-enable DMA using the Registry Editor ---- this worked on me! But I had to try that twice!


Sun, 2009-05-24 12:19 by Deals

i first time on your website. Thanks for detail post- i looked for solution for my problem.

Acer should link to your site from theirs

Tue, 2009-05-19 19:45 by Dhex

Ive two acer aspire one computers (the other one belongs to my aunt tho), both buyed at the same time. After a month of usage.. they both began getting slooooww. MP3 became choppy, mouse became slow when viewing Youtube and the blue memory exception screen apeared when using Limewire and listening music at the same time. I was blaming the Atom 1.6 processor as it showed hight usage everytime I did one of this tasks or even opening multiple explorer windows... I started to think it was a terrible processor.

After a couple hours of goggling and trying some solutions with no luck, I came to this site... and after trying the little program script, the problems where gone!!! Both computers are running smotly now... and the audio is again a charm. I spended some more time reading the whole think to understand what was going on and how to prevent it from happening again. Thank you so much!!! I was even thinking in selling this laptop.

..And now that i think about it.. there are some computers I know that I would like to check for this same issue.

Issue widespread

Thu, 2009-05-21 18:05 by admin

Yes, the issue is widespread. Sooner or later every computer running the Windows IDE drivers will develop it, if the computer is used sufficiently.

Good Solution

Mon, 2009-04-27 17:27 by ink price

It is good that you provide such solutions for common problems that exist. There are many people who strive to find proper solutions for their computer related problems. The posting of such information on the net would help them a great deal.


Mon, 2009-04-27 12:52 by w1cun

If you are not using the generic microsoft drivers (Defualt installation) for your Primary and Secondary IDE/ATA channels DO NOT try uninstalling the channel. This is because they will be most certainly detected on the next re-boot and re-installed, however the generic windows drivers will be installed in place of the MFR. propietary drivers and they will not work correctly! You will fall in to a trap. This happened to me with a Dell Dimension 8200 which uses Intel chipset drivers loaded in BIOS. One very good thing about Dell computers is that you can go to the Dell website and in downloads, enter your "service tag number" and come up with a list of downloads aprropiate for your machine. One of the options was a file enabling you to make a Boot Flash Bios disk. I was able to flash the bios and got the intel chipset dirvers back for the IDE/ATA controller. Bios on this 8200 by default had UDMA turned off but I entered setup on first boot after flashing the BIOS (F2) I turned UDMA on. I exited setup and let the system boot to XP normal. I looked in device manager for both IDE chanels and they both showed Transfer as UDMA 5 with the correct intel driver installed. The bottom line is that if you do not use generic MS drivers by default for the controller, DO NOT UNINSTALL THE CHANNEL if you have no way to put the correct driver back in. I hope I saved someone out there a giant head ache becuase I spent the better part of a day figuring this one out!!



Mon, 2009-04-27 16:37 by admin

Thanks a lot for this warning! I will change the text of the main article at the top accordingly and add an appropriate warning.

dandyes's picture

it doesn't work

Tue, 2009-04-21 02:03 by dandyes

when am runningit, windows give an error message like this :

script : c:\document and settings\administrator\my documents\software\resetdma.vbs
line : 1
char : 15
error : expected end of statement
code : 800A0401
source : microsoft VBscript compilation error

someone tell me why n how to solve this problem...thanks to all

Incomplete program file

Tue, 2009-04-21 05:56 by admin

One possibility is that the download didn't work properly and the program is damaged. Could you try to download it again?

The other possibility would be that Windows Scripting Host (WSH, wscript.exe) is not properly installed. On my Windows XP SP3 computer it is C:\WINDOWS\system32\wscript.exe version, 152 KB.

To all of you who still can't run in DMA mode. Please read this!

Sun, 2009-03-29 14:59 by robert4you

I am a "proud" owner of a Compaq Evo N1020v. When I bought it back in 2003, it came with a 30 GB, 4200 rpm Fujitsu harddrive. In December 2008 I decided to replace it with a WD 160 GB, since the fujitsu was to small. No matter what I did, the damn thing refused to work in DMA mode - the only mode it accepted was PIO. It drove me crazy... It was like driving a car with only one gear - the other four was missing. I talked to Microsoft Support, HP/Compaq, local computer stores and many "computer geeks" where I live - nobody could find a solution. I tried everything on this website, still nothing that solved my problem... Yesterday, I stumbled on something really, really interesting on the Internet which I think can help many with PIO - DMA problems. Keep on reading, please!

I would like to quote a man called Fred Jones, he wrote:

"I have studied and researched this extensively. The main issue is that when the original contrator for HP built the Ali M5229\M52xx hard drive controller, they designed the controller and driver to 80GB which was the top offering for this series before discontinuing. Ali was bought out by ULI, which in turn was bought out by nVidia. Without writing a book here, thats it. If you are upgrading with a 100+Gb HD, the driver defaults to PIO. Exactly why, you will need at least a dime store progamming\engineering degree which the guys who designed it originally must have had. It needs a new driver developed\tweaked to get beyond the 80Gb barrier. I am experiementing with some options and have tried many regedits and driver alternatives, and Drive utility tweaks and BIOS upgrades. They either freeze or blow out the OS partition. I'm using a Hitachi 160Gb and my next offering is to split the partition into 2 drives and use the drive tweaking utility to tell the BIOS it is a 80Gb drive. If anyone else has any solutions, please post here. I will be back when I find a solution and a prayer. Have a good one,,, two or three. Kindly, FJ."

Well, guess if we all got a solution to our frustating problem...

Another person called "Gose2010" wrote:

"Try to install the ide4008.exe.
you can download it here
After installing this the HDD shout work in DMA mode. I've had the same problem with a Samsung Harddisk but now it works great."

All I can say is that this file on 1 MB solved nearly four monhts of frustration for me. I am tremendously gratefull to "Gose2010".

To all who want to have further information about this, please go to:

Finally, my computer has five gears again and I can sleep at night ;-) My WD 160 GB runs in UDMA mode 5, as it should!

P.S. Many thanks for a great and important site!


Thu, 2009-03-26 20:24 by pmfurtado

The vbs worked!

I was suffering from very high level of hardware interrupts that were consuming almost all cpu particularly during disk activity...

It took a good number of hours until I find out that the IDE primary channel was running in PIO mode...

Thanks Guys! Really helpful stuff!


Simpler Solution

Mon, 2009-03-09 12:59 by tonesh

Many thanks to admin and Alexander Grigoriev for the method based on deleting MasterIdDataChecksum or SlaveIdDataChecksum. Fixed the problem - I don't know how you guys figure these things out.

Found that it can be fixed without the registry and reboot steps. Using Device Manager, IDE ATA/ATAPI Controllers, Secondary IDE Channel, (right-click) Properties, Advanced Settings, Device 0, Transfer Mode. Set to "DMA if available". Ok and exit Device Manager. Then go into Device Manager again, IDE ATA/ATAPI Controllers, Secondary IDE Channel, (right-click) Properties,and select Scan for Hardware Changes. This has the same effect as the reboot. Exit Device Manager, the problem should be fixed. Note that the problem can be recreated easily for test by setting the Tranfer Mode to "PIO Only" in Device 0, Transfer Mode.

This solution probably needs admin access to the machine - but then all these solutions probably do too.

Best wishes

Great find

Mon, 2009-03-09 14:48 by admin

Thanks for the good information! Could anybody please try this and confirm that it works in some more real-world circumstances?

I'm wondering whether and why it is necessary to exit and re-enter Device Manager, but I guess you've tried it without and it didn't work.

Good question

Thu, 2009-03-12 11:03 by tonesh

Hi Admin,

Good question. There is really no need to go out of Device Manager and go into it again. The "Scan for hardware changes" step will work immediately after Transfer Mode is set to "DMA if available".

It would be good to see if this works for intractable problems - for me it was just long-standing stuttering DVD performance.

Best wishes

Quick solution worked

Sun, 2009-03-08 07:32 by mkelley

[Re: See main article above, chapter "The trap",]

PIO mode is enabled by default in the following situations:

I believe this happened to me, and when I used the quick resolve [see main article above, chapter "Quick solution"],

If you're not interested in the details, but just want to fix this problem as quickly as possible:

  1. Click here.


my son found the research, and I tried it after 3 days of trying to rectify my problem, my main drive was running at 1/6 of it's normal speed. And it worked just as quickly, as the time to try the fix. I don't know the details, but it worked. THANK YOU all who input to this forum! mkelley

[This comment has been superficially edited by the admin. Thanks for the kind words.]

For the quick fix, I clicked on the word HELP but see only texts

Mon, 2009-10-12 09:15 by dreamtoys

What do I do next after seeing a page full of text?


Please also send answer to

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